Technical Field
The present invention generally relates to imaging of granular material, particularly relating to an imaging system for use in imaging and analysis of e.g. grain.
Background
Imaging systems are often used for determining, with digital image processing, if a product fulfils desired appearance requirements, to thereby register or eliminate products that are faulty in shape and colour, or damaged products. E.g. seeds, grains of salt, berries, tablets or other samples are inspected through such imaging systems and a connected subsequent image processing system can thereafter analyse the sample in real time and determine if the sample is faulty and should be removed or registered. Imaging systems do not have to be used for only detecting and discarding faulty or defective samples, but can also be used for determining quality of samples and collecting statistics for future evaluation of the sample. For best results the sample should be imaged around its entire periphery and a way to do this is with a V-shaped angled pair of mirrors between which the samples flow, as for example in US2006152741.
To facilitate the image processing by creating a homogeneous background against which the sample is clearly distinguished, the system is often provided with a background element such as in US2006152741. This is however not enough for obtaining several separate images of the sample against a completely homogeneous background, which is desirable. With a system arranged as in US2006152741 reflected light will furthermore reach the camera, which is added to the image and makes it more difficult for the image processing system to distinguish faults in the samples from disturbing stray light and inhomogeneity in the background of the image, not related to the sample. One of the problems with an inhomogeneous background is that it obstructs a subsequent analysis of the images. Inhomogeneous elements in the background may affect and disrupt an automated digital image processing and obstruct the analysis of the actual sample.
There is thus a need for imaging systems that overcome one or more of the problems mentioned above.